Feat: adds crosses/ crossesAt options to axis component

Author: mindline-analytics

docs/usage/shapes/chart.md

@@ -95,6 +95,32 @@ $shape->getPlotArea()->getAxisX()->setMinBounds(0);
 $shape->getPlotArea()->getAxisX()->setMaxBounds(200);
 ```
 
+#### Crossing
+
+For Axis, you can define where it should be crossed by the perpendicular/ horizontal axis trought `setCrossesAt`.
+The property can be defined by one of the three given constants or as an absolute value on the target axis.
+
+``` php
+use PhpOffice\PhpPresentation\Shape\Axis;
+
+$bar = new Bar();
+
+$shape = $slide->createChartShape();
+$shape->getPlotArea()->setType($bar);
+
+// Usage of constant: Horizontal axis will cross the Y-Axis at `0`
+$shape->getPlotArea()->getAxisY()->setCrossesAt(Axis::CROSSES_AUTO);
+
+// Usage of individual value: Horizontal axis will cross the Y-Axis at `3`
+$shape->getPlotArea()->getAxisY()->setCrossesAt('3');
+```
+
+| Constant             | Description              |
+| -------------------- | ------------------------ |
+| `AXIS::CROSSES_AUTO` | Axis crosses at zero.    |
+| `AXIS::CROSSES_MIN`  | Axis crosses at minimum. |
+| `AXIS::CROSSES_MAX`  | Axis crosses at maximum. |
+
 #### Outline
 
 You can define outline for each axis (X & Y).

src/PhpPresentation/Shape/Chart/Axis.php

@@ -38,6 +38,10 @@ class Axis implements ComparableInterface
     public const TICK_LABEL_POSITION_HIGH = 'high';
     public const TICK_LABEL_POSITION_LOW = 'low';
 
+    public const CROSSES_AUTO = 'autoZero';
+    public const CROSSES_MIN = 'min';
+    public const CROSSES_MAX = 'max';
+
     /**
      * Title.
      *
@@ -84,6 +88,11 @@ class Axis implements ComparableInterface
      */
     protected $maxBounds;
 
+    /**
+     * @var string
+     */
+    protected $crossesAt = self::CROSSES_AUTO;
+
     /**
      * @var string
      */
@@ -243,6 +252,26 @@ public function setMaxBounds(int $maxBounds = null): self
         return $this;
     }
 
+    /**
+     * @return string
+     */
+    public function getCrossesAt(): string
+    {
+        return $this->crossesAt;
+    }
+
+    /**
+     * @param string $value
+     *
+     * @return self
+     */
+    public function setCrossesAt(string $value = self::CROSSES_AUTO): self
+    {
+        $this->crossesAt = $value;
+
+        return $this;
+    }
+
     public function getMajorGridlines(): ?Gridlines
     {
         return $this->majorGridlines;

src/PhpPresentation/Writer/PowerPoint2007/PptCharts.php

@@ -2297,15 +2297,17 @@ protected function writeAxis(XMLWriter $objWriter, Chart\Axis $oAxis, string $ty
             return;
         }
 
+        $crossesAt = $oAxis->getCrossesAt();
+
         if (Chart\Axis::AXIS_X == $typeAxis) {
             $mainElement = 'c:catAx';
             $axIdVal = '52743552';
-            $axPosVal = 'b';
+            $axPosVal = $crossesAt === 'max' ? 't' : 'b';
             $crossAxVal = '52749440';
         } else {
             $mainElement = 'c:valAx';
             $axIdVal = '52749440';
-            $axPosVal = 'l';
+            $axPosVal = $crossesAt === 'max' ? 'r' : 'l';
             $crossAxVal = '52743552';
         }
 
@@ -2485,10 +2487,16 @@ protected function writeAxis(XMLWriter $objWriter, Chart\Axis $oAxis, string $ty
         $objWriter->writeAttribute('val', $crossAxVal);
         $objWriter->endElement();
 
-        // c:crosses
-        $objWriter->startElement('c:crosses');
-        $objWriter->writeAttribute('val', 'autoZero');
-        $objWriter->endElement();
+        // c:crosses "autoZero" | "min" | "max" | custom string value
+        if (in_array($crossesAt, ['autoZero', 'min', 'max'])) {
+            $objWriter->startElement('c:crosses');
+            $objWriter->writeAttribute('val', $crossesAt);
+            $objWriter->endElement();
+        } else {
+            $objWriter->startElement('c:crossesAt');
+            $objWriter->writeAttribute('val', $crossesAt);
+            $objWriter->endElement();
+        }
 
         if (Chart\Axis::AXIS_X == $typeAxis) {
             // c:lblAlgn

tests/PhpPresentation/Tests/Shape/Chart/AxisTest.php

@@ -61,6 +61,15 @@ public function testBounds(): void
         $this->assertNull($object->getMaxBounds());
     }
 
+    public function testCrossesAt(): void
+    {
+        $object = new Axis();
+
+        $this->assertEquals(Axis::CROSSES_AUTO, $object->getCrossesAt());
+        $this->assertInstanceOf(Axis::class, $object->setCrossesAt(Axis::CROSSES_MAX));
+        $this->assertEquals(Axis::CROSSES_MAX, $object->getCrossesAt());
+    }
+
     public function testFont(): void
     {
         $object = new Axis();

tests/PhpPresentation/Tests/Writer/PowerPoint2007/PptChartsTest.php

@@ -276,6 +276,54 @@ public function testAxisBounds(): void
         $this->assertIsSchemaECMA376Valid();
     }
 
+    public function testAxisCrosses(): void
+    {
+        $oSeries = new Series('Downloads', $this->seriesData);
+        $oSeries->getFill()->setStartColor(new Color('FFAABBCC'));
+        $oLine = new Line();
+        $oLine->addSeries($oSeries);
+        $oShape = $this->oPresentation->getActiveSlide()->createChartShape();
+        $oShape->getPlotArea()->setType($oLine);
+
+        $elementCrosses = '/c:chartSpace/c:chart/c:plotArea/c:catAx/c:crosses';
+        $elementCrossesAt = '/c:chartSpace/c:chart/c:plotArea/c:catAx/c:crossesAt';
+        $elementAxPos = '/c:chartSpace/c:chart/c:plotArea/c:catAx/c:axPos';
+
+        // Default autoZero
+        $this->assertZipXmlElementExists('ppt/charts/' . $oShape->getIndexedFilename(), $elementCrosses);
+        $this->assertZipXmlAttributeEquals('ppt/charts/' . $oShape->getIndexedFilename(), $elementCrosses, 'val', 'autoZero');
+        $this->assertZipXmlAttributeEquals('ppt/charts/' . $oShape->getIndexedFilename(), $elementAxPos, 'val', 'b');
+        $this->assertIsSchemaECMA376Valid();
+
+        // Crosses max
+        $oShape->getPlotArea()->getAxisX()->setCrossesAt(Axis::CROSSES_MAX);
+        $this->resetPresentationFile();
+
+        $this->assertZipXmlElementExists('ppt/charts/' . $oShape->getIndexedFilename(), $elementCrosses);
+        $this->assertZipXmlAttributeEquals('ppt/charts/' . $oShape->getIndexedFilename(), $elementCrosses, 'val', 'max');
+        $this->assertZipXmlAttributeEquals('ppt/charts/' . $oShape->getIndexedFilename(), $elementAxPos, 'val', 't');
+        $this->assertIsSchemaECMA376Valid();
+
+        // Crosses min
+        $oShape->getPlotArea()->getAxisX()->setCrossesAt(Axis::CROSSES_MIN);
+        $this->resetPresentationFile();
+
+        $this->assertZipXmlElementExists('ppt/charts/' . $oShape->getIndexedFilename(), $elementCrosses);
+        $this->assertZipXmlAttributeEquals('ppt/charts/' . $oShape->getIndexedFilename(), $elementCrosses, 'val', 'min');
+        $this->assertZipXmlAttributeEquals('ppt/charts/' . $oShape->getIndexedFilename(), $elementAxPos, 'val', 'b');
+        $this->assertIsSchemaECMA376Valid();
+
+        // Crosses custom value
+        $oShape->getPlotArea()->getAxisX()->setCrossesAt('10');
+        $this->resetPresentationFile();
+
+        $this->assertZipXmlElementNotExists('ppt/charts/' . $oShape->getIndexedFilename(), $elementCrosses);
+        $this->assertZipXmlElementExists('ppt/charts/' . $oShape->getIndexedFilename(), $elementCrossesAt);
+        $this->assertZipXmlAttributeEquals('ppt/charts/' . $oShape->getIndexedFilename(), $elementCrossesAt, 'val', '10');
+        $this->assertZipXmlAttributeEquals('ppt/charts/' . $oShape->getIndexedFilename(), $elementAxPos, 'val', 'b');
+        $this->assertIsSchemaECMA376Valid();
+    }
+
     public function testAxisFont(): void
     {
         $oSlide = $this->oPresentation->getActiveSlide();